There is known from U.S. Pat. No. 3,865,260 Wieschel et al, a compacting device comprising a movable part capable of moving independently above the bottom of the body, on the one hand, and on the other hand, of moving with a second mobile part superposed thereupon, a telescopic jack of great length when extended being required to move the assembly of both parts from the front to the rear of the body.
There is known through U.S. Pat. No. 3,802,585 of Churchman, a compacting device also comprising two superposed parts each having however a different control jack and in this case the top part comprises a jack of a great length.